The present invention is an improvement on the apparatus shown in my prior patent for a Tube Bending Machine and Carriage Therefor U.S. Pat. No. 3,974,676 and in a related prior patent for Positioning Servo and Control Mechanism U.S. Pat. No. 3,949,582. These patents describe improved tube bending machines in which a track mounted carriage carries a rotatable chuck and wherein a single fixed motor is provided to selectively advance the carriage along the track or rotate the chuck relative to the carriage. Selective drive from a single motor is achieved by use of a motor driven chain that engages a sprocket journalled on a carriage and geared to drive chuck. Brakes are provided to selectively stop rotation of the chuck or motion of the carriage so that when one is braked the other is driven.
Because of the selective and alternative nature of the drive of the above-mentioned prior patents, speed of the bending operation is limited by the need to perform tube advancement and rotation in sequence. In this arrangement the carriage is first advanced, without rotation of the chuck, and upon attainment of the desired longitudinal position, rotation to the selected plane of bend is accomplished. Furthermore, as speed of operation is increased, limits of machine components are approached so that for maximum speed of operation various drive components may be severely strained.
Accordingly, it is an object of the present invention to avoid or minimize above-mentioned problems.